The invention relates to a positioning device adapted to move objects along a feed path which is divided up into a number of sections all placed in a single, more particularly vertical plane, but running in different directions, using a holder, wherein such feed action more especially involves lifting, transport and lowering, the motion of the holder being produced in each feed path section by the motion of a piston and cylinder actuator.
If an object is to be moved from one point to another for positioning it, it is frequently impossible for motion to proceed along a single, direct or linear path; the path may be made up of a number of sections to ride past an intervening structure so that in each section the object is moved in different directions.
To take one example, an object which is placed on a support on which it is not possible for it be slid, firstly has to be lifted, then fed on the level and finally deposited at the desired point. Accordingly known positioning devices have a number of piston and cylinder actuators, one for each section of the path with one respective object holding means on their piston rods and which when moving the object have to pass it from one piston rod to another where one path section ends and another one begins. The feed path is thus divided up into a number of linear path sections. Since a number of suitably designed piston and cylinder units is required the structural complexity of known positioning devices is considerable and this makes them expensive. In addition, a complex controller is required in order to make possible synchronous transfer operations between the separate piston and cylinder actuators. Even so, transfer is not always perfect, for example because of jolts which in some cases may be the cause of damage to the objects being positioned. A further point to be considered is that owing to the division of tha path into sections the complete cycle will be slow and this is a disadvantage when use in mass production is contemplated, where high handling rates are required. Last but not least, abrupt acceleration and deceleration of the objects due to the motion of the separate piston rods lead to a very jerky handling action during feed.
It is also to be noted in this connection that known positioning devices have a very large overall size so that they may only be used at one particular point and they may not be shifted at short notice to another point of application.